In reality pi’s the key operator (6)
I believe the answer is:
typist
'key operator' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'in reality pi's the' is the wordplay.
'in' says the answer is hidden in the clue.
'TYPIST' is hidden within 'reality pis the'.
Can you help me to learn more?
(Other definitions for typist that I've seen before include "One using keyboard" , "Skilled keyboarder" , "Old secretary" , "Stenographer" , "The old-style secretary, for one" .)